Locking screw



g-31,19 8. ERDOONAN 2,448,213

LOCKING SCREW Filed Feb. 23, 1946 Inventor Everefl 241g flea/2cm.

Patented Aug. 31, 1948 UNITED STATES PATENT OFFICE LOCKING SCREW Everett Ray Doonan, Wichita, Kans. Application February 23, 1946, Serial No. 649,693

3 Claims.

This invention relates to new and useful improvements and structural refinements in locking screws, more particularly, to screws such as may be effectively and conveniently employed for the mounting of switches, receptacles, or the like, on electrical outlet boxes.

Such boxes are usually installed during the rough construction of a building and their inward spacing with respect to the subsequent finished wall cannot be readily determined. Resultingly, considerable adjustment is very frequently required in order to align the outlet box cover plate flush with the finished surface of the wall, this adjustment often involving mutilation of the surrounding plaster or other material employed for the finishing purpose.

It is therefore the principle of the invention to eliminate the difficulties above outlined by providing a screw of the character herein described, whereby the cover plate may be mounted on the outlet box flush with the finished wall surface, notwithstanding the relative positioning of said box to such surface.

In this manner, the installation of the outlet boxes is considerably simplified and the plaster finishing operation or the like, may be undertaken with little or no regard for the subsequent adjustment of the cover plate.

A further object of the invention is to provide a locking screw which, in addition to its use as already set forth, will lend itself generall wherever an adjustable locking connection of one article to another is required.

Another object of the invention is to provide a locking screw which is of simple construction and which may be readily and economically manufactured in large quantities.

With the above more important objects in view, and such other objects as may become apparent as this specification proceeds, the invention consists essentially of the arrangement and construction of parts as illustrated in the accompanying drawings, in which:

Figure 1 is a cross-sectional view, showing the invention in use in the outlet box structure.

Figure 2 is a side elevation of the screw per se.

Figure '3 is a top plan View of the same,

Figure 4 is a cross-sectional view, taken in the plane of the line 4-4 in Figure 2, and

Figure 5 is a fragmentary front plan view showing a portion of the outlet box and switch, and the invention in association therewith.

Like characters of reference are used to designate like parts in the specification and throughout the several views.

Referring now to'the accompanying drawings in detail, more particularly to the Figures 2 to 4 inclusively, the invention consists of a screw comprising the conventional shank 5 and the integral head designated generally by the reference character 6.

The screw head is of an elongated configuration and is formed in the opposite ends and side portions thereof with kerfs defining the keeper grooves I. The latter are disposed medially the thickness of the head and the inner ends of the grooves are obliquely cut to constitute the relatively parallel wedge-shaped portions 8. These wedges are disposed in the head at the diametrically opposed sides of the shank 5 and their purpose will be hereinafter more fully described.

The outer surface of the head 6 is formed with the conventional screw driver slot 9 or alternatively, the head may be adapted for co-action with another suitable tool, such as :a wrench.

The outlet box I0 is mounted in the wall II in any conventional manner, the box being provided with screw-threaded ears l2 into which the shanks -5 may be threaded. The mounting ,plate l3 of the switch (or receptacle) I4 is usually provided with elongated screw openings IS, the configuration of the head 6 being such as to render the same receivable in these openings.

When the invention is placed in use, it is only necessary to adjust the screws in the ears l2 so that the heads 6 are positioned substantially as shown with respect to the wall surface 16, whereupon the plate |3 of the associated switch or receptacle is passed over the .heads 6, in alignment with the grooves l.

The screws are now turned through approximately so that the grooves engage the edges of the openings 15, and the wedge-shaped portions 8 will be found to co-act in a turn-button manner with said edges to lock the head 6 in the openings Hi.

The cover plate I! may now be attached to the plate l3 by means of the screws I8, the plate I! being aligned flush with the surface [6 of the wall II, as will be clearly apparent from the accompanying Figure 1.

If the plate I1 is not properly aligned with the surface IS, the heads 6 should be turned in the opposite direction to unlock the same from the openings 15, and by rotating the shanks 5 in the cars 12, the subsequent positioning of the plate I! with respect to the wall I I and the associated boX I0 may be adjusted as required.

It should be noted that the box ill, the associated switch or receptacle [4 and. the plates 13 and 3 I1 constitute no part of the present invention, the same being confined exclusively to the structure of the locking screw, substantially as set forth.

While in the foregoing there has been shown and described the preferred embodiment of this invention it is to be understood that minor changes in the details of construction, combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention as claimed.

What I claim as my invention is:

1. In association with an article having an elongated screw opening, a locking screw comprising in combination, a threaded shank and an elon" gated head thereon, said head being removably receivable in said opening and formed 'in the 'op portions thereof with kerisg posite ends and side 7 said kerfs defining keeper grooves disposed me:

dially the thickness of said head, the innerends of said grooves being obliquely cut and cons-tituting relatively parallel wedge-shaped portions in said head at the diametrically opposed sides of said shank, said grooves engaging the edges of s'aid'opening and said wedge-shaped portions co-acting in a turn-button manner with said edges to lock said head in said opening when said screw assumes a predetermined angular position.

2. The device as defined incla'im 1, in which said head is formed in the outer surface thereof with a diametrically extending screw driver slot.

3. [For association with an outlet box formed with an elongated screw opening, a locking screw comprising in combination, a threaded shank and an elongated head thereon, said head having a diametrically extending screw driver slot formed in the outer surface thereof and being receivable in said opening, said head also being formed in the, opposite end and side portions thereof with Keri-s, said kerf defining keeper grooves disposed medially the thickness of said head, the inner ends of said grooves being obliquely cut and constituting relatively parallel wedge-shaped portions in said head at the diametrically opposite sides of said hank, said grooves engaging the 'ed'ges'of said opening and said wedge-shaped portio rsgogacting in a turn-button manner with said edges o lock said head in said opening when said scrw' as'sumes a. predetermined angular position.

U EVERETT RAY DOONAN.

Zini tshesmseimn flhefollowingireferences' are of record in the fileflofthispatentl UNITED STATES PATENTS Number- "Name-g Date 

